Electrical power generator

ABSTRACT

An improved system for generating electrical power using a fuel cell. More particularly, a system for generating hydrogen gas by reacting water vapor with a substantially non-fluid substance and transporting the generated hydrogen gas to the fuel cell which generates electrical power. Reacting water vapor with the non-fluid hydrogen generating substance rather than liquid water prevents caking of the non-fluid substance and deposition of byproducts onto the non-fluid substance that interfere with continued generation of hydrogen gas. Also, a non-electrically actuated valve for use in a hydrogen gas generating apparatus which regulates the generation of hydrogen as required by the fuel cell.

CROSS REFERENCE TO RELATED APPLICATION

[0001] This application is a continuation in part of co-pending U.S.patent application Ser. No. 09/941,247 filed Aug. 28, 2001 which isincorporated herein by reference, and claims the benefit of co-pendingU.S. provisional patent application serial No. 60/448,573 filed Feb. 19,2003.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The invention relates to an improved system for generatingelectrical power using a fuel cell. More particularly, the inventionpertains to a system for generating hydrogen gas by reacting water vaporwith a substantially non-fluid substance in a regulated manner, andtransporting the generated hydrogen gas to the fuel cell which in turngenerates electrical power. The invention also relates to a pneumaticvalve for use in a hydrogen gas generating apparatus.

[0004] 2. Description of the Related Art

[0005] Similar to batteries, fuel cells function to produce electricpower through chemical reactions. Rather than storing reactants asbatteries do, fuel cells are operated by continuously supplyingreactants to the cell. Proton exchange membrane (PEM) fuel cellsoperating with H₂ from hydrocarbon liquids have emerged as leadingcandidates to replace batteries in portable electronic devices, powercleaners, more fuel efficient vehicles and for poweringmicroelectromechanical systems (MEMS) devices such as MEMS electricalpower generators. In a typical fuel cell, hydrogen gas acts as onereactant and oxygen as the other, with the two reacting at electrodes toform water molecules and releasing energy in the form of direct currentelectricity. This direct current electricity may then be converted intoan alternating current. The system may produce electricity continuouslyas long as hydrogen and oxygen are provided. While oxygen is typicallyprovided from the air, it is generally necessary to generate hydrogengas from other compounds through controlled chemical reactions ratherthan storing hydrogen, because storing of hydrogen gas requires that iteither be compressed or cryogenically cooled. As fuel cell technologyevolves, so do the means by which hydrogen gas is generated forapplication with fuel cells.

[0006] Currently, there are various methods which are known and employedfor generating hydrogen gas. The predominant method is by a processknown as reformation in which fossil fuels are broken down into theirhydrogen and carbon products. However, this system is undesirable in thelong term because it is dependent upon a non-renewable resource. Anothermethod is electrolysis, in which hydrogen is split from water molecules.However, this method is not well suited for large scale applications,such as use in automobiles. Another means of generating hydrogen gas isby reversibly adsorbing and releasing hydrogen gas from metal hydridesor alloys through heating. While this method is useful, it is notpreferred because the metal hydrides are typically very heavy, expensiveand only release small quantities of hydrogen. Yet another means bywhich hydrogen gas is generated is through reactive chemical hydrides.This process involves chemically generating hydrogen gas from dry,highly reactive solids by reacting them with liquid water or acids.Chemicals especially suitable for this process are lithium hydride,calcium hydride, B₁₀H₁₄, lithium aluminum hydride and sodiumborohydride, each of which are capable of releasing plentiful quantitiesof hydrogen. The disadvantages associated with this method is thatreaction products from the chemical and liquid water typically form acake or pasty substance which interferes with further reaction of thereactive chemical with the liquid water or acid.

[0007] It is of great interest in the art to provide a means by whichhydrogen gas may be generated in a regulated manner for use in fuelcells, without relying on non-renewable resources and without thedisadvantages of each of the aforementioned methods. The presentinvention provides a solution to this problem. The invention provides anelectrical power generator and a process for controllably generatinghydrogen gas at the rate that a fuel cell requires it. The electricalpower generator comprises a water vapor generator at least partiallyfilled with water vapor, at least one hydrogen gas generator connectedto the water vapor generator, a regulating valve and a fuel cellconnected to the hydrogen gas generator, the hydrogen generation chamberbeing at least partially filled with a substantially non-fluid substancewhich reacts with water vapor to generate hydrogen gas. The hydrogen gasgenerated may then be used as a “fuel” which allows the fuel cell togenerate electrical power. The present invention improves upon therelated art by reacting a water vapor with a substantially non-fluidsubstance to controllably generate hydrogen gas, rather than liquidwater. By reacting a water vapor with the aforementioned non-fluidchemical substance, it has been found that the typical problemsassociated with reactive chemical hydrides are avoided, resulting in amore efficient system than those of the prior art.

[0008] The invention also provides a non-electrically actuated valvesuitable for use in hydrogen generating apparatuses. The valve of theinvention is actuated by hydrogen overpressure to regulate the diffusionof water vapor into a powdered chemical fuel. Since the valve isnon-electrically actuated, the need for a control voltage, a controllerand a control voltage generator is eliminated, and the problem ofelectrical discharge in valves operating in humid conditions is avoided.

SUMMARY OF THE INVENTION

[0009] The invention provides an electrical power generator comprising:

[0010] a) a water vapor generator;

[0011] b) a hydrogen gas generator attached to the water vaporgenerator, said hydrogen generator containing a substantially non-fluidsubstance which reacts with water vapor to generate hydrogen gas; saidhydrogen generator optionally being attached to said water vaporgenerator via at least one conduit; and

[0012] c) a fuel cell attached to the hydrogen gas generator; said fuelcell optionally being attached to said hydrogen gas generator via atleast one conduit.

[0013] The invention also provides a process for generating hydrogen gasfor fueling a fuel cell comprising:

[0014] a) directing water vapor from a water vapor generator to ahydrogen generator, said hydrogen generator being at least partiallyfilled with a substantially non-fluid substance which reacts with watervapor to generate hydrogen gas; and

[0015] b) directing said hydrogen gas and any residual water vapor to afuel cell.

[0016] The invention further provides an improved process for generatingelectrical energy wherein water and hydrogen gas are directed from awater containing chamber to a fuel cell; and water and any residualhydrogen gas are directed from the fuel cell back to the watercontaining chamber; and water and hydrogen gas are directed through ahydrogen gas generator, which hydrogen gas generator is connected toeach of the fuel cell and water containing chamber and which hydrogengas generator is at least partially filled with a substance which reactswith water to generate hydrogen gas, wherein the improvement comprisescontacting water in the form of water vapor with a substantiallynon-fluid substance which reacts with water vapor to generate hydrogengas.

[0017] The invention still further comprises a hydrogen gas generatingapparatus, the apparatus comprising a housing which encloses:

[0018] a) a water vapor generator;

[0019] b) a hydrogen gas generator, comprising a substantially non-fluidsubstance that reacts with water vapor to generate hydrogen gas;

[0020] c) at least one conduit connecting the water vapor generator andthe hydrogen gas generator, the conduit allowing for the flow of watervapor from the water vapor generator to the hydrogen gas generator; and

[0021] d) a valve positioned through said conduit for alternatelyopening and closing the conduit, said valve comprising:

[0022] i) a flexible diaphragm having a periphery that is fixed to saidhousing;

[0023] ii) a valve disc positioned opposite the diaphragm and matingwith the conduit for alternately opening and closing the conduit;

[0024] iii) a rod connector having opposite ends, the rod extendingthrough a portion of the conduit and attached at one of its ends to thediaphragm and attached at its opposite end to the valve disc; and

[0025] iv) a seal attached around a periphery of the conduit andpositioned for mating with the valve disc when the valve disk ispositioned to close the conduit.

BRIEF DESCRIPTION OF THE DRAWINGS

[0026]FIG. 1 is a schematic representation of an electrical powergenerator having a conduit and a separate return line.

[0027]FIG. 2 is a schematic representation of an electrical powergenerator having neither a conduit nor a return line.

[0028]FIG. 3 is a schematic representation of an electrical powergenerator having a conduit connecting each of the water vapor generator,the hydrogen gas generator and the fuel cell, and also having a pump, atensile membrane within the water vapor generator and a thermalinsulator around the fuel cell.

[0029]FIG. 4 illustrates the components for the electronic controlsystem and the overall interconnection scheme of the electrical powergenerator.

[0030]FIG. 5 is a perspective view of the electrical power generatorformed within a polymeric block.

[0031]FIG. 6 illustrates a perspective view of an electrical powergenerator and its component parts, in the form of a thin molded card.

[0032]FIG. 7 is a graph of voltage current measurement of the electricalpower generator.

[0033]FIG. 8 illustrates a schematic representation of a mesovalve.

[0034]FIG. 9 illustrates a perspective view of a mesovalve.

[0035] FIGS. 10A-10I illustrate the process steps for forming a MEMSfuel cell.

[0036]FIG. 11 is a cross-sectional side-view of a hydrogen gasgenerating apparatus of the invention having a non-electrically actuatedvalve.

[0037]FIG. 12 is a top-view of a hydrogen gas generating apparatus ofthe invention regulated by a non-electrically actuated valve.

[0038]FIG. 13 is a cross-sectional side view of a hydrogen gasgenerating apparatus of the invention having a non-electrically actuatedvalve.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0039] An electrical power generator is provided which generateshydrogen gas through controlled reactions of water vapor with asubstantially non-fluid substance, which hydrogen gas is then used tofuel a fuel cell. The electrical energy generated may be used to powerminiature devices such as wireless sensors, cellular phones or otherhand held electronic devices.

[0040] A seen in FIGS. 1-3, the electrical power generator 10 broadlycomprises at least one water vapor generator 12, at least one hydrogengas generator 14 attached to the water vapor generator 12 and a fuelcell 16 attached to the hydrogen gas generator 14. The water vaporgenerator 12 is preferably a chamber that is at least partially filledwith water in the form of either water vapor, liquid water or ice. Thequantity of either liquid water or ice may vary and generally depends onthe size of the water vapor generating chamber 12 and the applicationfor which the power generator 10 is used. If a liquid is used, theliquid may comprise a mixture of water and alcohol, in any proportion,to prevent the liquid water from freezing until very low temperatures.In this case, the water vapor generator may generate both water andalcohol vapors. Both vapors may then enter the hydrogen generator andinduce the generation of hydrogen. The preferred embodiment is to usepure water.

[0041] Should a liquid water be present within the water vapor generator12, the liquid water may be prevented from seeping out of the watervapor generator 12 by either porous plugs 24 or by a valve 26. Porousplugs 24 comprise a porous material such as cotton or a polymericfabric, which acts as a barrier to liquid water while allowing thepassage of water vapor into and out of the water vapor generator 12.

[0042] Alternately, valve 26, may regulate the passage of water vaporout of the water vapor generator 12 and prevent the seeping out of anyliquid water. This embodiment is shown in FIG. 2. The valve 26 may beeither a manually or pneumatically or electrically controlled valve. Thepreferred embodiment is a pneumatically controlled valve. If the valveis controlled electrically, the initial power necessary to open thevalve, causing an initial flow of water vapor from the water vaporgenerator 12 to the hydrogen gas generator 14, is preferably supplied bypower stored in a device 30. The valve 26 may be directly electricallyconnected to the device 30 or to the fuel cell 16, with the fuel cellthen being electrically connected to the device 30. The device 30 mayalternately be attached to either the water vapor generator 12, thehydrogen gas generator 14 or another element of the power generator 10.Once the valve 26 is initially opened to allow water vapor out of thewater vapor generator 12, the power generated from the fuel cell 16 isthen preferably used to supply the power for controlling the valve 26.In the preferred embodiment of the invention using an electricallycontrolled valve, the device 30 comprises a battery. The opening andclosing of the valve 26 is preferably controlled pneumatically dependingon when it is desired to generate hydrogen gas and fuel the fuel cell.Electrically controlled valves of several types exist. Preferably theelectrically controlled valve is a mesovalve. Structures for usefulmesovalves are shown in FIGS. 8 and 9. Mesovalves are also described inU.S. Pat. No. 5,836,750, which is incorporated herein by reference. Aseries of mesovalves forms a mesopump. Such ultra-light compact,water-vapor diffusive-flow regulator mesovalves, use anelectrostatically actuated moving polymer membrane. Control of themesovalve actively regulates the internal pressure of the generatorsince it controls water vapor access to the powder fuel chamber.

[0043] While valve 26 is only depicted in FIG. 2, it is intended thatany embodiment of the present invention may include at least one valve26. Further, several different arrangements of interconnecting the fuelcell, hydrogen generator, water vapor generator, valves and pumps areavailable as is evident to persons familiar with gas and vaporinterconnections. It should be understood that when elements herein aredescribed as being attached or connected together that they may beeither directly or indirectly attached, unless a direct attachment isspecified. Also, when the flow of water vapor and/or hydrogen gas isdescribed herein, it should be understood that the gases may flowdirectly or indirectly from one element to another, unless particularlyspecified. For example, hydrogen gas may flow from the hydrogen gasgenerator to a fuel cell indirectly by the hydrogen gas first passingthrough the water vapor generator.

[0044] In the preferred embodiment, the power generator 10 is initiallyloaded with hydrogen gas within at least one of said water vaporgenerator 12, hydrogen gas generator 14, fuel cell 16 and said optionalconduits 18 or return line 20. This initial loading of hydrogen gas willtravel to the fuel cell 16, causing a reaction within the fuel cell, andgenerating electricity. This electricity is then used to power the valve26. In the preferred embodiment of the invention, the power generator isalways filled with hydrogen during operation. Furthermore, the fuel cellmay be fed with hydrogen of lower or higher humidity, according to itsexact attachment, so that the hydration of the fuel cell may beadjusted. The humidity of the hydrogen is higher in the water vaporgenerator, and lower in the hydrogen generator.

[0045] The dimensions of the water vapor generator 12 are preferablyvery small in scale, but may also vary with respect to the use of thepower generator 10. In preferred small scale embodiments, the watervapor generator 12 is preferably from about 0.1 cm to about 1.0 cm inheight, from about 0.1 cm to about 1.0 cm in width and from about 0.1 cmto about 1.0 cm in length. As seen in FIG. 3, optionally within thewater vapor generator is a tensile membrane 32. The tensile membrane 32acts to exert pressure on water vapor within the water vapor generator12 forcing the water vapor out of the water vapor generator 12 andtoward the hydrogen gas generator 14. The pressure within the watervapor generator 12 is preferably maintained at a pressure of slightlymore than atmospheric pressure.

[0046] Attached to the water vapor generator 12 is a hydrogen gasgenerator 14. The hydrogen gas generator 14 is preferably in the form ofa chamber and is at least partially filled with a substantiallynon-fluid substance which reacts with water vapor to generate hydrogengas. Alternately, the hydrogen gas generator 14 may be a volume adjacentto the water vapor generator 12 suitable for retaining the non-fluidsubstance. Similar to the water vapor generator 12, the dimensions ofthe hydrogen gas generator 14 will vary depending on the proposed use ofthe power generator 10. When the hydrogen gas generator 14 comprises achamber in a small scale application, it is preferably from about 0.1 cmto about 1.0 cm in height, from about 0.1 cm to about 1.0 cm in widthand from about 0.1 cm to about 1.0 cm in length.

[0047] The substantially non-fluid substance within the hydrogen gasgenerator 14 preferably comprises a material in powder, granule orpellet form and is preferably an alkali metal, calcium hydride, lithiumhydride, lithium aluminum hydride, B₁₀H₁₄, sodium borohydride, lithiumborohydride, and combinations thereof. Suitable alkali metalsnon-exclusively include lithium, sodium and potassium. The preferredmaterials for the non-fluid substance are sodium borohydride, lithiumborohydride and lithium aluminum hydride. The non-fluid substance isalso preferably combined with a hydrogen generation catalyst to catalyzethe reaction of the water vapor and the non-fluid substance. Suitablecatalysts include non-exclusively include cobalt, nickel, ruthenium,magnesium and alloys and combinations thereof.

[0048] Attached to the hydrogen gas generator 14 is a fuel cell 16.Hydrogen powered fuel cells are well known in the art. The dimensions ofthe fuel cell 16 also depend on the intended use of the power generator10. In small scale applications, the fuel cell is preferably from about0.1 cm to about 0.2 cm in height, from about 0.1 cm to about 1.0 cm inwidth and from about 0.1 cm to about 1.0 cm in length. As seen in FIG.3, it is preferred that the fuel cell 16 is at least partiallysurrounded by a thermal insulator 28. The thermal insulator 28 maycomprise anything suitable to maintain the fuel cell above the freezingtemperature of water. Suitable thermal insulators non-exclusivelyinclude insulators comprising a plastic foam. In addition to the thermalinsulator, a heater 34 may be placed adjacent to or attached to the fuelcell 16 to maintain the temperature of the fuel cell and power generator10 above the freezing temperature of water. In the preferred embodimentof the invention, the power generator 10 will be maintained at atemperature of from about −20° C. to about 50° C., more preferably fromabout 0° C. to about 50° C. and most preferably from about 20° C. toabout 50° C. while in use.

[0049] As seen in FIGS. 1 and 3, the water vapor generator 12 ispreferably connected to the hydrogen generator 14 via at least oneconduit 18 containing a valve, and the hydrogen generator 14 ispreferably connected to the fuel cell 16 via at least one conduit 18.The conduits 18 may also connect to the water vapor generator so thatmore humid hydrogen is passed to the fuel cell. The conduits 18 maycomprise anything sufficient to facilitate the transport of water vaporfrom the water vapor generator 12 to the hydrogen generator 14 andhydrogen gas from the hydrogen generator 14 to the fuel cell 16. As seenin FIG. 1, in the preferred embodiment of the invention, the powergenerator 10 also includes a return line 20 that directs any residualwater vapor and hydrogen gas from the fuel cell 16 back to the watervapor generator 12. The return line 20 is preferably substantiallyidentical to conduits 18. As shown in FIG. 2, neither the conduits 18nor the return line 20 are necessary elements for the efficientperformance of the invention. In this embodiment, the water vaporgenerator 12 may be directly attached to the hydrogen gas generator 14and the fuel cell 16 directly attached to the hydrogen gas generator 14.

[0050] It is further preferred that at least one pump 22 is coupled withthe power generator 10 to pump hydrogen gas and water vapor between thewater vapor generator 12 and the hydrogen gas generator 14. The pump 22is preferably electrically connected to and powered by the fuel cell 16,with the pump optionally being powered initially by power stored indevice 30. In a preferred embodiment, the pump is a mesoscopic pump, ormesopump. One preferred mesopump is described in U.S. Pat. No.5,836,750, which is incorporated herein by reference. It is alsopreferred that an inert gas is initially present within the water vaporgenerator 12, hydrogen gas generator 14, fuel cell 16 and in theoptional conduits 18 and optional return line 20. The inert gas assistsin transporting water vapor and hydrogen gas to the fuel cell 16 and ispreferably a gas selected from the group consisting of nitrogen, argon,combinations thereof and the like.

[0051] In use, the water vapor generator 12 may generate water vapor ina variety of ways, such as by evaporation of liquid water from the watervapor generator 12, by diffusion of water molecules into the air, bybubbling gas through the water, or by passing gas over the surface ofthe liquid water or the ice if present or over surfaces wetted by thewater, or by pumping water so as to induce a higher vapor generationrate. Once the water vapor is generated it is directed from the watervapor generator 12 toward the hydrogen gas generator 16 either viadiffusion, via pressure exerted by tensile membrane 32, via a forcegenerated by pump 22, by a flow induced as water vapor is consumed inthe hydrogen generator, or by flow induced as hydrogen is consumed bythe fuel cell. The water vapor then passes through either the porousplugs 24 or open valve 26, preferably into conduit 18 and then to thehydrogen gas generator 14 which is at least partially filled with thesubstantially non-fluid substance. Once the water vapor passes into thehydrogen gas generator 16, the substantially non-fluid substance reactswith the water vapor, consuming water vapor to generate hydrogen gas.The hydrogen gas and any residual water vapor is then directed from thehydrogen gas generator 14 to the fuel cell 1, preferably via anotherconduit 18. Once the hydrogen gas reaches the fuel cell, the hydrogengas is reacted with oxygen gas within the fuel cell, consuming thehydrogen gas to generate electricity. Subsequently, any residual watervapor and any residual hydrogen gas are transported from the fuel cell16 back to the water vapor generator 12, preferably via a return line20.

[0052]FIG. 4 shows preferred components for the electronic controlsystem and the overall interconnection scheme of the electrical powergenerator. A closed loop drive and feed back control circuit is providedfor the fluid drive control and output voltage control. An importantrequirement is to control the pumping rate of fuel, water or watervapor, in order to maintain an adequate flow and pressure of hydrogen inthe fuel cell and to accommodate the electrical power required by theload. An active control system regulates the output voltage, and forsome applications, to store electrical energy in a small device such asa lithium button cell or capacitor for applications requiring very fastbursts of high electrical power. A microcontroller-based electroniccircuit uses conventional components such as a voltage multiplier, pumpdriving circuit, signal conditioning circuit, and low power controlcircuit. Appropriate sensors allow internal functions to be measured andcontrolled. Electrical power storage systems such as a lithium buttoncell or a super capacitor and a gas energy reservoir (hydrogen storage)are alternate methods of providing for short high power (burst mode)operation, and initial startup from long term storage.

[0053] Preferably, all of the above mentioned component parts of thepower generator including the water vapor generator, the hydrogen gasgenerator, the fuel cell, the optional conduits, mesopump and mesovalveare formed within a polymeric block composed of a material such as apolyethylene, a polyimide, a polycarbonate, an acrylic, or combinationsthereof. A representation of the electrical power generator and itscomponent parts formed within a polymeric block is shown in FIG. 5. Thepolymer package provides protection of the gas diffusion electrodes fromstresses of the outside world and allows a way to attach the fuel cellelectrically to the outside world, and further allows the fuel cellcathode to passively consume oxygen from air, and further allows theanode to be plumbed into the hydrogen generator in a planar assembly.Generators in the form of a molded card are inexpensive, light weight,impermeable and inert, and the required components can be readilyincorporated and linked with fluid and electrical interconnections. Arepresentation of the electrical power generator and its componentparts, in the form of a thin molded card is shown in FIG. 6.

[0054] The inventive electrical power generator employing a MEMS PEMfuel cell with actively-regulated hydrogen generator, fueled by waterand a solid chemical, has an energy density significantly greater than alithium battery. Such may be produced in a range of standard sizes, in asimilar manner to the series of batteries AAA, AA etc. Such generatorsare capable of supplying the following minimum characteristics: 2.7Vnominal voltage (2.5 to 3.5V), 70 uA mean output current; 30 mA, 100msec power pulses at an average rate of 1 every 10 minutes (for dataTx/Rx), 0° C. to 65° C. operation, >10 year shelf life, 1 year operation(1.6 Watt hours) and maximum 1 gram weight. The generator will becapable of lifetimes of more than 10 years by simply adding more storedfuel. Unlike alkaline or lithium batteries, the generator is capable ofcomplete shutdown, and hence in principle offers unlimited shelf life,and operational life only limited by the stored fuel. This is animportant advantage over batteries for commercial applications. FIG. 7shows a graph of typical voltage current measurement of an electricalpower generator according to the invention. FIGS. 10A-10I show theprocess steps for forming a MEMS fuel cell.

[0055] The invention also provides a hydrogen gas generating apparatusthat utilizes a non-electrically actuated valve to regulate the flow ofwater vapor from a water vapor generator to a hydrogen gas generator.This apparatus is illustrated in FIGS. 11-13. FIG. 11 is across-sectional side-view of a hydrogen gas generating apparatus showingthe component parts of the valve. FIG. 12 is a top-view of the hydrogengas generating apparatus showing the preferred shape and position of thecomponent parts of the apparatus. As shown in FIGS. 11 and 12, the valveis positioned through a conduit 44 that connects a water vapor generator12 and a hydrogen gas generator 14, allowing for the regulated passageof water vapor and hydrogen gas between the water vapor generator andthe hydrogen gas generator. The valve itself comprises a pneumaticallyactuated flexible diaphragm 36 having a periphery that is fixed to theapparatus housing 48; a valve disc 38 positioned opposite the diaphragm36 and mating with the conduit 44 for alternately opening and closingthe conduit 44; a rod connector 40 having opposite ends, the rod 40extending through a portion of the conduit 44 and attached at one of itsends to the diaphragm 36 and attached at its opposite end to the valvedisc 38; and a seal 42 attached around a periphery of the conduit 44 andpositioned for mating with the valve disc 38 when the valve disk 38 ispositioned to close the conduit 44. In a preferred embodiment of theinvention, the diaphragm 36 also comprises an outer surface of thehousing.

[0056] As seen in the figures, the valve is positioned through theconduit 44 for alternately opening and closing the conduit 44. Morespecifically, when the conduit 44 is open, water vapor is allowed topass from the water vapor generator 12 to the hydrogen gas generator 14,resulting in hydrogen gas generation. When the conduit is closed, thevalve disc 38 mates with the seal 42, preventing the flow of water vaporand hydrogen gas through the conduit 44. In the preferred embodiment ofthe invention, a fuel cell 16 is joined with the hydrogen gas generatingapparatus, which fuel cell 16 is capable of consuming the generatedhydrogen gas to generate electricity. The fuel cell 16 may be attacheddirectly to any component of the apparatus, e.g. to water vaporgenerator 12 or hydrogen generator 14, or indirectly via a suitablechannel.

[0057]FIG. 13 illustrates a cross-sectional view of an alternateembodiment of a power generator including a fuel cell 16 and having anidentical non-electrically actuated valve regulating the flow of watervapor from a water vapor generator to a hydrogen gas generator. In thisembodiment, a water vapor generator 12 surrounds a hydrogen gasgenerator 14. As water vapor is generated by the water vapor generator12, it preferably diffuses into a conduit 44 through a suitable membrane46. Membrane 46 may comprise a tensile membrane, porous plugs or a valvesuch as those described for the embodiments of FIGS. 1-3. Similar to theembodiment of FIGS. 11 and 12, a valve is positioned through conduit 44that connects the water vapor generator 12 and hydrogen gas generator14, regulating the flow of water vapor from the water vapor generator 12to the hydrogen gas generator 14. Further, in this embodiment, there ispreferably a particulate filter present between the hydrogen gasgenerator 14 and the fuel cell 16 that allows hydrogen gas to pass intothe fuel cell 16, but prevents the non-fluid substance from reaching thefuel cell 16.

[0058] The actuation of the valve is controlled by the differentialpressure between atmospheric pressure, i.e. external pressure, and theinternal hydrogen gas pressure of the apparatus. As the internal gaspressure of the apparatus rises above atmospheric pressure due to thegeneration of hydrogen gas, the diaphragm 36 will bend outward slightly.This causes the connector 40 to pull the valve disc 38 against the seal42, closing the valve and preventing the flow of additional water vaporto the hydrogen gas generator 14. With the valve closed, hydrogenproduction ceases. This also prevents the internal gas pressure fromrising further. As hydrogen is consumed, such as by a fuel cell 16, theinternal gas pressure drops, allowing the valve disc 38 to disengage theseal 42 and opening the valve. Accordingly, hydrogen gas isautomatically produced at the rate at which it is consumed. Further,when a fuel cell 16 is attached to the apparatus, hydrogen gas will beavailable for consumption by the fuel cell at all times, as somequantity of hydrogen will consistently be present in the apparatus.

[0059] In the preferred embodiment of the invention, the internal H₂pressure of the apparatus when in the closed position is from about 1psi to about 10 psi, more preferably from about 1 psi to about 5 psi,and most preferably from 1 psi to about 2 psi. More particularly, thevalve will be fully shut when no hydrogen gas is used by the fuel cell,and will open the amount required to meet consumption rate of thehydrogen gas. In the preferred embodiment of the invention, an internalhydrogen gas pressure of greater than 1 psi will maintain the valve inthe conduit closed position. In the most preferred embodiment of theinvention, the internal pressure of the power generator is maintained atabout 2 psi at all times, wherein when the pressure drops below about 2psi, the valve will open slightly until the internal pressure raises toat or above about 2 psi, causing the valve to close. As described above,the valve is controlled by the pressure of the hydrogen gas and thevalve also regulates the internal pressure of the hydrogen gas.

[0060] The dimensions of the component parts are preferably very smallin scale but may vary with respect to the particular application of thevalve. In the preferred embodiment of the invention, the diaphragm 36preferably comprises a thin circular plate preferably having a diameterof from about 1 cm to about 3 cm, more preferably from about 1 cm toabout 2 cm. The valve disc preferably has a diameter of from about 0.2to about 1 cm, more preferably from about 0.2 cm to about 0.5 cm. In thepreferred embodiment of the invention, the rod connector 40 may comprisea screw or a bolt, but any other means of connecting the diaphragm 36 tothe valve disc 38 is suitable such that the valve can alternately openand close the conduit. Each of the diaphragm 36, valve disc 38 and seal42 may be fabricated of a suitable polymeric material, but may alsocomprise a metal composite material as determined by the requirements ofthe intended use of the valve.

[0061] While the present invention has been particularly shown anddescribed with reference to preferred embodiments, it will be readilyappreciated by those of ordinary skill in the art that various changesand modifications may be made without departing from the spirit andscope of the invention. It is intended that the claims be interpreted tocover the disclosed embodiment, those alternatives which have beendiscussed above and all equivalents thereto.

What is claimed is:
 1. An electrical power generator comprising: a) awater vapor generator; b) a hydrogen gas generator attached to the watervapor generator, said hydrogen generator containing a substantiallynon-fluid substance which reacts with water vapor to generate hydrogengas; said hydrogen generator optionally being attached to said watervapor generator via at least one conduit; and c) a fuel cell attached tothe hydrogen gas generator; said fuel cell optionally being attached tosaid hydrogen gas generator via at least one conduit.
 2. The powergenerator of claim 1 further comprising at least one conduit connectingthe water vapor generator to the hydrogen gas generator and at least oneconduit connecting the generator to the fuel cell.
 3. The powergenerator of claim 1 further comprising a return line which directsresidual water vapor and hydrogen gas from the fuel cell to the watervapor generator.
 4. The power generator of claim 1 wherein the watervapor generator comprises a chamber at least partially filled withwater.
 5. The power generator of claim 1 wherein the water vaporgenerator comprises a chamber at least partially filled with a mixtureof water and alcohol.
 6. The power generator of claim 1 wherein thewater vapor generator comprises a chamber at least partially filled withwater vapor.
 7. The power generator of claim 1 wherein the water vaporgenerator is at least partially filled with ice.
 8. The power generatorof claim 1 wherein the hydrogen gas generator comprises a chamber atleast partially filled with a substantially non-fluid substance whichreacts with water vapor to generate hydrogen gas.
 9. The power generatorof claim 1 wherein the hydrogen gas generator comprises a chamber atleast partially filled with a substantially non-fluid substance whichreacts with a mixture of alcohol and water vapor to generate hydrogengas.
 10. The power generator of claim 1 further comprising hydrogen gasinitially loaded within at least one of said water vapor generator,hydrogen gas generator, fuel cell and said optional conduits.
 11. Thepower generator of claim 1 further comprising at least one deviceattached to at least one of said water vapor generator, said hydrogengenerator or said fuel cell for causing an initial flow of water vaporfrom the water vapor generator to the hydrogen gas generator.
 12. Thepower generator of claim 1 wherein said substantially non-fluidsubstance comprises a material selected from the group consisting ofalkali metals, calcium hydride, lithium hydride, lithium aluminumhydride, B₁₀H₁₄, sodium borohydride, lithium borohydride andcombinations thereof.
 13. The power generator of claim 1 wherein saidsubstantially non-fluid substance comprises sodium borohydride.
 14. Thepower generator of claim 1 wherein said substantially non-fluidsubstance comprises lithium borohydride.
 15. The power generator ofclaim 1 wherein said substantially non-fluid substance comprises lithiumaluminum hydride.
 16. The power generator of claim 1 further comprisinga hydrogen generation catalyst combined with said substantiallynon-fluid substance.
 17. The power generator of claim 16 wherein saidcatalyst is selected from the group consisting of cobalt, nickel,ruthenium and alloys and combinations thereof.
 18. The power generatorof claim 1 further comprising at least one pump for pumping hydrogen gasand water vapor between the water vapor generator and the fuel cell. 19.The power generator of claim 18 wherein the at least one pump comprisesa mesopump.
 20. The power generator of claim 1 further comprising atleast one valve for regulating the passage of water vapor between thewater vapor generator and the hydrogen gas generator.
 21. The powergenerator of claim 20 wherein the at least one valve comprises amesovalve.
 22. The power generator of claim 20 wherein the at least onevalve is controlled by gas pressure within the power generator.
 23. Thepower generator of claim 20 wherein the at least one valve regulates gaspressure within the power generator.
 24. The power generator of claim 1further comprising porous plugs adjacent to said water vapor generator,said plugs substantially impeding the flow of liquid water from saidwater vapor generator and substantially allowing the flow of hydrogengas and water vapor into and out of said water vapor generator.
 25. Thepower generator of claim 1 wherein said substantially non-fluidsubstance is in powder, granule or pellet form.
 26. The power generatorof claim 1 wherein said fuel cell is at least partially surrounded by athermal insulator.
 27. The power generator of claim 1 further comprisinga heater adjacent to the fuel cell.
 28. The power generator of claim 1further comprising a tensile membrane within the water vapor generatorwhich exerts pressure directing water vapor from the water vaporgenerator to the hydrogen gas generator.
 29. The power generator ofclaim 1 wherein the water vapor generator, the hydrogen gas generator,said fuel cell and said optional conduits are formed within a polymericblock.
 30. The power generator of claim 29 wherein the polymeric blockcomprises a polyethylene, a polyimide, a polycarbonate, an acrylic, orcombinations thereof.
 31. A process for generating hydrogen gas forfueling a fuel cell comprising: a) directing water vapor from a watervapor generator to a hydrogen generator, said hydrogen generator beingat least partially filled with a substantially non-fluid substance whichreacts with water vapor to generate hydrogen gas; and b) directing saidhydrogen gas and any residual water vapor to a fuel cell.
 32. Theprocess of claim 31 wherein a mixture of water vapor and alcohol vaporare directed to the hydrogen generator.
 33. The process of claim 31further comprising: c) directing any residual water vapor and anyresidual hydrogen gas from the fuel cell back to the water vaporgenerator.
 34. The process of claim 31 further comprising directingwater vapor and any present hydrogen gas from the water vapor generatorto the hydrogen generator via at least one conduit, and directinghydrogen gas and any residual water vapor from the hydrogen gasgenerator to the fuel cell via at least one conduit.
 35. The process ofclaim 31 further comprising directing water vapor and any presenthydrogen gas from the water vapor generator to the hydrogen generatorvia at least one conduit, and directing said hydrogen gas and anyresidual water vapor to the fuel cell via at least one conduit; andreturning any residual water vapor and any residual hydrogen gas fromthe fuel cell to the water vapor generator via at least one return line.36. The process of claim 31 wherein the water vapor generator comprisesa chamber at least partially filled with water vapor.
 37. The process ofclaim 31 wherein the passage of said water vapor from the water vaporgenerator to the hydrogen generator is controlled by at least one valve.38. The process of claim 37 which valve is valve controlled by thepressure of said hydrogen gas.
 39. The process of claim 31 wherein saidsubstantially non-fluid substance comprises a material selected from thegroup consisting of alkali metals, calcium hydride, lithium hydride,lithium aluminum hydride, sodium borohydride, lithium borohydride, andcombinations thereof.
 40. The process of claim 31 wherein saidsubstantially non-fluid substance comprises lithium borohydride.
 41. Theprocess of claim 31 wherein said substantially non-fluid substancecomprises sodium borohydride.
 42. The process of claim 31 wherein saidsubstantially non-fluid substance comprises lithium aluminum hydride.43. The process of claim 31 wherein said substantially non-fluidsubstance is in powder, pellet or granule form.
 44. The process of claim31 further comprising pumping said water vapor and any present hydrogenfrom said water vapor generator to said hydrogen gas generator.
 45. Theprocess of claim 44 wherein the pumping is conducted with a mesopump.46. The process of claim 31 further comprising heating said fuel cellwith a heater.
 47. The process of claim 31 comprising directing watervapor from the water vapor generator to the hydrogen gas generator bypressure from a tensile membrane within the water vapor generator. 48.The process of claim 31 further comprising causing an initial flow ofwater vapor from the water vapor generator to the hydrogen gas generatorvia at least one device attached to at least one of said water vaporgenerator, said hydrogen generator or said fuel cell.
 49. In an improvedprocess for generating electrical energy wherein water and hydrogen gasare directed from a water containing chamber to a fuel cell; and waterand any residual hydrogen gas are directed from the fuel cell back tothe water containing chamber; and water and hydrogen gas are directedthrough a hydrogen gas generator, which hydrogen gas generator isconnected to each of the fuel cell and water containing chamber andwhich hydrogen gas generator is at least partially filled with asubstance which reacts with water to generate hydrogen gas, wherein theimprovement comprises contacting water in the form of water vapor with asubstantially non-fluid substance which reacts with water vapor togenerate hydrogen gas.
 50. The process of claim 49 wherein saidsubstantially non-fluid substance comprises lithium borohydride.
 51. Theprocess of claim 49 wherein said substantially non-fluid substancecomprises sodium borohydride.
 52. The process of claim 49 wherein saidsubstantially non-fluid substance comprises lithium aluminum hydride.53. A hydrogen gas generating apparatus, the apparatus comprising ahousing which encloses: a) a water vapor generator; b) a hydrogen gasgenerator, comprising a substantially non-fluid substance that reactswith water vapor to generate hydrogen gas; c) at least one conduitconnecting the water vapor generator and the hydrogen gas generator, theconduit allowing for the flow of water vapor from the water vaporgenerator to the hydrogen gas generator; and d) a valve positionedthrough said conduit for alternately opening and closing the conduit,said valve comprising: i) a flexible diaphragm having a periphery thatis fixed to said housing; ii) a valve disc positioned opposite thediaphragm and mating with the conduit for alternately opening andclosing the conduit; iii) a rod connector having opposite ends, the rodextending through a portion of the conduit and attached at one of itsends to the diaphragm and attached at its opposite end to the valvedisc; and iv) a seal attached around a periphery of the conduit andpositioned for mating with the valve disc when the valve disk ispositioned to close the conduit.
 54. The hydrogen gas generatingapparatus of claim 53 which further comprises a fuel cell connected tothe housing in a manner allowing for the flow of generated hydrogen gasinto said fuel cell.